Fix compile error in client/x11/Makefile
Fix compile error in client/x11/Makefile

BUG=https://github.com/ibus/ibus/pull/18
TEST=client/x11/Makefile

Review URL: https://codereview.appspot.com/217590043
Patch from Hodong Kim <hodong@cogno.org>.

Keruspe/ibus,fujiwarat/ibus,j717273419/ibus,ibus/ibus,j717273419/ibus,j717273419/ibus,Keruspe/ibus,Keruspe/ibus,j717273419/ibus,ibus/ibus,fujiwarat/ibus,ibus/ibus,fujiwarat/ibus,fujiwarat/ibus,Keruspe/ibus,ibus/ibus